Gas sensors or gas detectors are devices that determine the presence and/or measure the concentration of a target gas. Many sensors, such as metal oxide gas sensors based on Tin (SnO3), Indium (In2O3) or Tungsten (WO3) for example, exhibit good sensitivity to some gases such as nitrogen dioxide (NO2). Typically, these sensors also exhibit high sensitivity to ozone (O3). This makes them difficult to use as gas detectors/sensors in ambient air measurements due to the presence of O3.
Systems for limiting sensor exposure to ozone are known. Such systems may utilise an ozone scrubber in front of the gas sensor to limit the exposure of the device to ozone. The ozone scrubber for example may use chemicals that react with ozone to convert it into another substance less affective to the sensor, or use a catalyst that converts ozone into oxygen. Such scrubbers however tend to produce reaction products that may be corrosive to the sensor material and/or affect the operability of the sensor.
It is an object of the present invention to provide an improved system and method for mitigating the effects of unwanted gas on a gas sensor and/or to at least provide the public with a useful choice.